Grey vs Black border for on foot VR

[buzzx]

Would black be a better colour for the outside border when on foot in VR?
Examples below.
Maybe even an option to choose your own colour?
Not sure if maybe even a gradient or some form of graphic would be possible but you would think a simple colour option would be easy to enable.

 

[Celedon]

I have thought black would be better since I first played it.

 

[Sysmon]

Neutral grey, as is used, is less hard on the eyes. Takes a while to get used to perhaps.

S